Signaling system for railroads



Feb. 5, 1935. A. LANGDON' SIGNALING SYSTEM FOR RAILROADS Filed June 25,1952 2 Sheets-Sheet 1 INVENTOR MM ATTORNEY Feb. 5, 1935. A. LANGDONSIGNALING SYSTEM FOR RAILROADS 2 Sheets-Sheet 2 Filed June 23, 1952 BY Jt Flllilllill Patented Feb. 5, 1935 UNI-TED STATES 1,989,992 SIGNALINGSYSTEM FOR RAILROADS- Andrew Langdon, Rochester, N. Y., assignor toGeneral Railway N. Y.

Signal Company, Rochester, g}

Application June 23, issaserial No. 618,922

' 11 Claims.

This invention relates to railway signaling, and

more particularly to a check lock circuit for assuring safe interlockingbetween the signals governing the entrance of trailic at opposite endsof a single track section. 1 I

Sometimes it I happens that two interlocking plants are located only ashort distance apart, and that these interlocking plants are connectedby several single tracks, each of which normally allows traffic to movein a particular direction, but wherein it may be necessary to reversethe direction of traffic in such section due to congestion, repairsbeing made on other tracks, or the like. Suitable interlocking meansmust of course be provided to prevent trafiic being set up in bothdirections on said single track, check lock or traffic section at onetime, and means must be provided for preventing changing the directionof traffic with a train in or approaching the traffic section, unlessproper safeguards are introduced.

In accordance with the present invention it is proposed to employ tworelays in series, one located at each of the entering ends to suchsingle track section, preferably called lever repeating relays, and toemploy a second circuit, preferably called a direction circuit, forchecking whether or not these two lever repeating relays are incorresponding positions, and to allow traffic to be set up in onedirection when these two lever repeating relays are energized and to beset up in the opposite direction when these two relays are deenergized,the checking circuit being employed to assure against conflicting signalindications being given as might otherwise occur if energy wereaccidentally applied to an intermediate point of the circuit includingthe two relays in series, for under this condition one of these relayscould be energized and the other remain deenergized. The checkingcircuit referred to is also employed as a means for selecting betweenafl'ili- 1 ated signal controlling circuits to enable a re duction' inthe line wire requirements between the two ends of the check locksection, this being one of the-primary purposes for controlling non}-automatic' or call onsignals.

Other objects, purposes and characteristic features of the presentinvention reside in theprovision of suitable time measuring safety meansto prevent sudden changes in the direction of traffic being set up,which might endanger a fast moving train approaching either in suchsection or in an approach section.

Other objects, purposes and characteristic features of the presentinvention will in part be obvious from the accompanying drawings andwill in part be more specifically pointed out hereinafter. i

In describing the invention in detail reference may be had to theaccompanying drawings, in which:-

Fig. 1 shows a check'lock circuit embodying the present invention forcontrolling non-automatic call-on signals; and

Fig. 2 illustrates one manner in which auto matic signals may besup'erimposed on the system shown in Fig. l to advantage, so that onepair of line wires sufiices to control the home and distant indicationsof two opposing signals associated with the check lock section.

Structure of Fig. 1

Referring to Fig. 1 of the drawings, the track rails 5 have been showndivided into track sections by insulating joints 6, one section of whichconstitutes the single track section to which the check lock circuit ofthe present invention has been shown applied. It is of course understoodthat suitable switches and crossovers will be em.- ployed beyond theextremities of'the single track section in question, these trackswitches, crossovers, and the like (not shown), constituting theinterlocking plants located at opposite ends of this check lock section.The check 'lock section in question is provided with the usual trackcircuit including the track relay T and the track battery '7. The normaldirection of traffic in thissingle track section is preferably from leftto right, or west to east, as indicated by the arrow.

At the east end of the single track section has been shown anon-automatic or call-on signal for controlling the movement .of trafficinto said section from that end, asimilar call-on signal being shown atthe west end thereof. In the approach section to these signals 10 and 20have been shown track relays T and T being repeated by approach stick.relays A8 and AS respectively, these approach stick relays having as-Sociated'therewith suitable timing devices such .as thermal relays TRand 'IR v respectively.

At the west end of the single track section has been shown an operatorstower OT, in which there is a lever L'for setting up a particulardirection of traffic over the single track section. ,This controllingoffice may be located'at a considerable distancefrom the check locksection, without sacrifice of safety, even though only one line wire andcommon are employed between the operators tower and the rear end of thecheck lock section. When this lever L is moved to its abnormal positionit energizes a circuit including the lever repeating relays DB andDRconnected in series, the relay DB being located near the signal 10 andthe relay DB being located near the signal 20. In order to assure thatno conflicting signal indications can be given, as for instance mightotherwise be true if the line wire 10 were accidentally connected to anunauthorized source, the direction relays 130 and DC have been provided.As is obvious from the drawings one of these relays DC or D0 dependingon whether the relays DR and DB are energized or deenergized, isenergized through a circuit including the contacts of relays DB and DBassuming corresponding positions. For instance, the relay D0 is shown inits energized condition and is energized through back contacts of therelays DB and DB in series. This en ergizing circuit may be traced asfollows: beginning at the terminal of a suitable source of current,front contact 9 of relay DC wire 11, polar contact 12 of this samerelay, wire 13, back contact 14 of the relay DB wires 15, 16 and 17,back contact 18 of the relay DB wire 19, winding of the relay D0 wire20-, back contact 21 of relay DB wires 22, 23 and 24, back contact-25 ofthe relay DB wire 28, polar contact 27 of the direction check relay D0wire 28,

neutral contact 29 of the relay D0 and to the other terminal of saidsource.

The track relay T is also repeated through a track stick relay TS, thepick-up circuit for which may be traced as followsz beginning at theterminal of a suitable battery, front contact 30 of the direction relayD0 wire 31, polar contact 32 of this same relay, wire 33, back contact34 of the relay DB wires 35 and 36, front contact 37 of the track relayT, wires 38 and 39, through the winding of the relay TS and to the otherterminal of said battery.

It will be noted that the relay TS remains up even though the trackrelay T drops, this through current flowing'in the following stickcircuit:-- beginning at the terminal of said battery, front contact 30of the relay D0 wire 31, polar contact 32 of this same relay, wire 33,back contact '34 of the relay DB wires 35 and 40, heating coil 41 of therelay TR, wire 42, stick contact 43 of the relay TS, wires 44 and 39,winding of the relay TS to the other terminal of said battery. It willbe noted that the stick circuit just traced includes the correspondencecontacts 32 and 34 of relay D0 and DB respectively.

From this stick circuit it is apparent that if a direction of traflic ischanged while the track relay T is deenergized the track repeater stickrelay TS will also be deenergized, and that this relay TS may only bepicked up after an interval of time if the track relay T remainsdeenergized, this through the medium of the contact 45 of the thermalrelay TR. It may be pointed out here, that the flow of current in theheating coil 41 results inclosure of the contact 45 shunting the contact37, but that with the relay TS picked up and stuck up the closure of itscontact 50 will 'beof no avail until the thermal relay has been fullycooled under "which condition its contact '52 is reclosed. Any othersuitable time element device may be employed in lieu of 'a thermal relayif desired, or this protection may, if desired,

be omitted. Also, it will be noted that the callon signal 2C cannot beenergized and cleared unless the tl'iermal relay TR is in its normalcon- 'dition, thus requiring this relay TR to return to only if thethermal relay TB, is in its normal cooled condition, wire 53, frontcontact 54 of the relay DC wire 55, polar contact 56 of this same relay,wire 57, signal mechanism of the call-on signal 2C and to the otherterminal The direction relay DC is normally energized through thefollowing circuit:- beginning at the terminal of a suitable battery,back contact 50 of the thermal relay TR wire 61, front contact '62 ofthe approach stick relay AS wire 63, back contact 64 of the relay DBwire 65, winding of the relay DC wire 66, back contact 67 of the relayDR and to the other terminal of said battery. The purpose of the thermalrelays TR and TR is the same as that of the thermal relay TR, namely tocause a retarded pick-up of a stick relay, followed by another period ofdelay necessary to allow cooling of this thermal relay before completionof a second circuit.

Operation of Fig. 1

It will be noted that the call-on signal 20 is in the call-on positionwhereas the call-on signal 1C is at stop, so that traflic may move inthe normal direction as indicated by the arrow. Let us now assume thatthe operator in the tower OT moves his lever to the reverse position,this in order to set up west-bound trafiic on the single track section.movement of the lever L will energize the direction relays DB and DBthereby breaking the energizing circuits for the relays D0 and D 3heretofore traced.

Picking up of the relay DB will by its lifting of the contact 34 destroythe condition of correspondence between the contacts 32 and 34 of relaysDC and DR so the relay TS will be deenergized, but since the relay D0 isoperated to its reverse polarity position, after the period of timerequired for the signal 20 to assume the stop position to close itscontact 8 to complete the pick-up circuit for relay AS thecorrespondence between the contacts 32 and 34 is reestablished and ifthe relay T is in its energized condition the relay TS is again pickedup without the intervening operation of the thermal relay TR. The relayAS if once up is of course stuck up through its stick contact 88. Alsoif relay T is down, relay A8 will not be picked up until the thermalrelay TR has been energized and closed its front contact.

Picking upof the relay DB will thus result in immediate energization ofthe direction relay DC with current of reverse polarity through thefollowing circuit;- beg-inning at the terminal back contact 70 of thethermal relay TR wire '71, front contact 72 of the approach relay ASwire 73, front contact 21 of relay Di wire 20, winding of the relay D0wire 19, front contact 18 of the relay DB and to the other terminal Itshould be noted that the direction of current flow through the directionrelay DC has now been reversed, so that its polar contacts assume theleft-hand dotted position, as a result of which the circuit for thecall-on signal 20 is broken at the polar contact 56 of the relay D0 inaddition to the break previously made at the contact 50 of relay TS.

With the lever repeating relays DR, and DB now both energized and withthe direction relay DC assuming its left-hand polar position, thedirection relay DC is energized through the following circuit:-beginning at the terminal front contact 50 of the track stick relay TS,wire 51, back contact 52 of the thermal relay TR, wire 53, front contact54 of the relay D0 wire 55, polar contact 56 of this relay'assuming itslefthand position, wire 75, front contact 76 0f the relay DB wires '77,16 and '78, front contact 64 of relay DB wire 65, winding of relay DCwire 66, front contact 67 of relay DB wires 68, 23 and 69, front contact79 of relay DB wire 80, polar contact 81 of relay D0 wire 82,frontcontact 83 of relay DC and to the other terminal It is thus seenthat the relays DB and DB must assume corresponding positionsin' orderto energize the direction relay at one end ofv the single track section,and furthermore, that the polar direction relay at the other. end ofthis section must be energized to the proper polar position. Analyzingthe various checks from a slightly different angle, it should be notedby referring to Fig. 1, that energization of the relay DR, or DB for anyreason, will result in deenergization of the relay D0 this because itsenergizing circuit includes back contacts of both of the re-- lays DRand DB and that with relay D0 deenergized the call-on signal 2C cannotbe set in the call-on position. Furthermore, in order to energize thecall-on signal 1C at the other end of the single track section requiresits associated relay D0 to assume a polar position, which it can onlyobtain by current flowing over the line wires 16 and 23, and then onlyif the relays DB and DB are both energized and the relay DC assumestheproper polar position, so that there are numerous checks which must besatisfied before the call-on signal 1C can be placed in its proceedposition if the system formerly assumed the normal position, andsimilarly, if the direction of traflic, has once been reversed, numerouschecks must be satisfied before normal direction of traiiic can be setup by the other of the signals 1C or 2C.

Structure of Fig. 2

Fig. 2 shows conventionally the same apparatus as shown in Fig. 1 (manyparts thereof having been omitted for convenience), but in addition tothis apparatus shows how the main semi-automatic signals 1 and 2associated respectively with the call-on signals 1C and 20 may becontrolled. Since the system shown in Fig. 1 affords two polar relays D0and DC always assuming when energized corresponding polar positions,this feature may be taken advantage of for transmitting favorableindications both caution and clear to the semi-automatic three-positionsignals 1 or 2, one at a time, in accordance with the direction oftravel permitted at that time. In other words, the line wires and 91 mayat one time be employed to control the home relay 2H for governing thesignal 2, as is normally the case in Fig. 2 of the drawings, but withthe polar relays D0 and D0 reversed the same line wires 90 and 91 may beused to control the home relay 11-1 for governing the signal 1.

It will be noted that the polarity of energization of the home-relay21-1 is reversed by dropping of track relay T through the medium ofcontacts 86 and 8'7 of track relay T thereby placing the signal 2 in itscaution position signifying that the second block in advance isoccupied. Also, it should be noted that dropping of the track relay T,through the medium of its contacts 92 and 93, will result indeenergization of the home relay 2H, thereby placing the signal 2 in thestop position manifesting that the block immediately in advance of thesignal 2 is occupied. Similarly, if the relays DC and DC assume theleft-hand polar position, signifying west-bound traffic, the home relay11-1 is controlled to a polar position depending upon the position ofcontacts 94 and 95 of the track relay T but'relay 1H is deenergized ifthe track relay T is deenergized, this for reasons already explained..In other words, both of the relays DC and D0 must have their neutralcontacts 96, 9'7, 98 and 99 closed, before a home relay 1H or 2H can beenergized, and their polar contacts 160, 101, 102 and 103 must assumecorresponding positions before either of these home relays IE or 2H canbe energized, and these home relays. 1H and 2H are furthermorecontrolled by the track relay of the block next in advance'and the trackrelay of the second block in advance of the signal controlled by suchhome relay.

In the arrange ent shown in Fig. 2 the call-on signals 1C and 2C arecontrolled in exactly the same way as they are in thearrangement shownin Fig. 1 of the drawings, except that their associated semiautomaticsignal 1 or 2 must assume the stop position before such call-on signalcan assume its call-on position. This requisite is carried out by theprovision of the semaphore contact 57 operated by the signal 2 in thecontrol circuit for the call-on signal 20, a similar contact 59 beingincluded in the circuit for the call-on signal 1C.

It may be pointed out that (see Fig. 1) the approach stick relay AS canonly be energized if the non-automatic signal 20 is at stop and if oncedeenergized cannot be picked up by placing the signal 2C to stop untilafter a period of delay necessitated by the thermal relay included inits ick-up circuit, but that this delay is cancelled if there is notrain in the approach section to the signal 2C due to the shunt aifordedby the front contact 85 of the track relay T What has been said aboutthe relay AS is also true of the relay A8 with respect to its associatedapparatus. Referring, however, to Fig. 2 it will be noted that theheating coil of the thermal relay TR includes the semaphore contact 8 ofsignal 20 and contact 8 of signal 2 in series, so that both of thesesignals must be at stop to afford a heating circuit for this thermalrelay. What has been said about signals 2 and 2C and their associatedthermal relay is also true of signals 1 and 1C and their associatedrelay (not shown in Fig. 2).

It should be noted that the semi-automatic signals 1 and 2 arecontrolled in the usual way by the home-and-distant relays 1H and 2Hrespectively, the caution and clear wires being designat- 1 ed cc andcl, respectively. For the signal 2, for instance, the caution wire ca orthe clear wire cl is selected by the polar contact 105, and neither ofthese wires can have current applied thereto unless the neutral contact106 of relay 21-1 is closed.

Having thus shown a check lock circuit for a particular purpose, thischeck lock circuit, including numerous checks which must be satisfiedbefore the function which isto be performed can be carried out, and theinvention having been shown applied to a particular problem, it is to beunderstood that the underlying checking features disclosed herein may beapplied to other problems encountered in railway signaling, and thatmodifications and additions may be made to adapt the present inventionto the particular problem encountered in practicing the same, allwithout departing from the spirit or scope of the invention, except asdemanded by the scope of the following claims.

What I claim as new is:-

1. In combination, a track section, a signal at each end of said sectionand governing the entrance of trains into that end of said section, aneutral relay associated with each of said signals,

a manually controlled circuit for at times energizing said relays inseries, a signal control relay 'associa d with one of said signals forcontrolling that s and a circuit, inch; ing front contacts c each ofsaid neutral relays, for-energizing nal control relay, said circuitbeing governed hy traiiic conditions in approach to said other signal.

2. In combination, a track section, a signal at each end of said sectionand governing the entrance of trains into that end of said section, aneutral relay associated with each of said signals, a manuallycontrolled circuit for at times energizing said relays in series, asignal control relay associated with one of said signals for controllingthat signal, and a circuit for said signal control relay, circuit beinggoverned by said other signal and traffic conditions in approach theretoand including front contacts of said n-eutral'relays.

3. In combination, a track section, a signal at each end of said sectionand governing the entrance of trains into that end of said section, aneutral relay associated with each of said signals, manually controlledcircuit for at times energizing said relays in series, a signal. controlrelay associated with one of said signals for controllin that signal, acircuit for said signal control relay including front contacts of saidneutral relays, and means allowing closure of said circuit following theputting to stop or" said other signal only after said other signal hasbeen put to stop a predetermined time if a train is in approach thereto.

I? o railway nal s the combination with a 5 "le track section, a signalat each end of said section and governing the entrance of trains intothat end of said section, a neutral relay associated with each'of acircuit for at times energizing said relays, a second relay associatedwith each of said signals, and wires extending along sai: section forenergizing one or the other or" second relays depending upon whether thecontacts of two first mentioned clays are in picked up or retractedpositions.

' g 1 system, the combination section, a signal at each'end of saidsection and governing the entrance of into that end of said section, aneutral e ay associated with each aid signals, a cirfor at times energi,ng relays, a polar relay associated with each of said signals, and cirwies exten ng along said section for encrone 0: th trier polar relays inacordance with the energized or deenergized conon of said two firstmentioned relays. In a i combination with a l c on, a si nal at each endsaid secti n 9 "ning the entrance of trains into i 11 l l 0;. d section,neutral relay associated with ten of said s a cirrel ys, a secondcircuit cuit for energ inclu ugh front contacts of said a for clearingone of nials .ine controlled contact for allo lng signals, only atopened for a predetei ltrol oi other of a d second circuit has bee time.

the combination with a'single track a n, a signal at each *end of saidsection and governing the entrance of trains into that end of saidsection, a neutral relay associated with each of saidsignals, a'circuitfor at times-energizing said-relays, a second circuit including a relaycontrolled through front contacts of said first mentioned two relays forcontrolling "one of said'signals, and a third circuit including anotherrelay and controlled "through backcontacts of said first mentioned times"energizing said relays, asecond relay associated with each of saidsignals, wires extending along said section for energizing one or theother of said second relays 'dependingupon the positicns of the contactsof said two first mentioned relays, a home-and-distant relay for eachsignal,

and other wires-extending along said section for at times controllingone and at other times controlling the other of said home-and-distant"relays depending upon the positions of the contacts of said two secondrelays.

9. In a railway signal system, the-combination with a single tracksection, a signal at each end of said section and ing th entrance oftrains into that end of said section, a relay associated with each ofsaid signals, a circuit including said relays in series for at timesenergizing said relays, and two other circuits including the same linewires at times energized from one end wiih a relay at the other and attimes energized from the other end with a relayat said one enddependingupon the condition of energizaticn of said twofirst mentionedrelays, for controlling said signals in accordance with theconditions'in said section and in the next section in advance for theparticular signal.

10. In a railway signal system, theccrnbination with a single tracksection, of a signal at each-end of said section for governing theentranceof trains into that end or section, a neutral relay associatedwith each of said signals, a manually controlled contact, a circuit forenergizing said neutral relays in so when said contact is closed, asecond relay associated with each of said signals, a secondcircuit'including one of said second relays and front contacts ofsaidfirst mentioned two relays for controlling one'of said signals, anda third circuit including the other of said second relays and backcontacts of said first mentioned two relays'for controlling the other ofsaid signals.

'11. In combination, a track section, a signal at each end of saidsection and governing the entrance oftrains into that end of saidsection, a neutral relay associated with each of said signals, amanually controlled circuit for at times energizing said relays inseries, a signal control relay associated with one of said signals forcontrolling that signal, a circuit for said signal control relayincluding 'frontcontaots of said neutral re lays, and means allowingclosure of said circuit following the putting to stop of said othersignal only after said other-signalhas been put to stop a predeterminedtime if there is a train in said track section.

ANDREW LANGDON

